Pastry

Pastry is a major type of bakers' confectionery. It includes many of the various kinds of baked products made from ingredients such as flour, sugar, milk, butter, shortening, baking powder, and eggs. Small tarts and other sweet baked products are called pastries. Common pastry dishes include pies, tarts, quiches and pasties.

Pastry can also refer to the pastry dough, from which such baked products are made. Pastry dough is rolled out thinly and used as a base for baked products.

Pastry is differentiated from bread by having a higher fat content, which contributes to a flaky or crumbly texture. A good pastry is light and airy and fatty, but firm enough to support the weight of the filling. When making a shortcrust pastry, care must be taken to blend the fat and flour thoroughly before adding any liquid. This ensures that the flour granules are adequately coated with fat and less likely to develop gluten. On the other hand, overmixing results in long gluten strands that toughen the pastry. In other types of pastry such as Danish pastry and croissants, the characteristic flaky texture is achieved by repeatedly rolling out a dough similar to that for yeast bread, spreading it with butter, and folding it to produce many thin layers.

Pastry (DHT)

Pastry is an overlay and routing network for the implementation of a distributed hash table (DHT) similar to Chord. The key-value pairs are stored in a redundant peer-to-peer network of connected Internet hosts. The protocol is bootstrapped by supplying it with the IP address of a peer already in the network and from then on via the routing table which is dynamically built and repaired. Because of its redundant and decentralized nature there is no single point of failure and any single node can leave the network at any time without warning and with little or no chance of data loss. The protocol is also capable of using a routing metric supplied by an outside program, such as ping or traceroute, to determine the best routes to store in its routing table.

Overview

Although the distributed hash table functionality of Pastry is almost identical to other DHTs, what sets it apart is the routing overlay network built on top of the DHT concept. This allows Pastry to realize the scalability and fault tolerance of other networks, while reducing the overall cost of routing a packet from one node to another by avoiding the need to flood packets. Because the routing metric is supplied by an external program based on the IP address of the target node, the metric can be easily switched to shortest hop count, lowest latency, highest bandwidth, or even a general combination of metrics.